Refactor unittests

tests/compiler/dart2js/serialization/analysis_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.serialization_analysis_test;
 
 import 'dart:async';
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/common/backend_api.dart';
 import 'package:compiler/src/common/names.dart';
 import 'package:compiler/src/compiler.dart';
 import 'package:compiler/src/filenames.dart';
-import 'memory_compiler.dart';
-import 'serialization_helper.dart';
-import 'serialization_test_data.dart';
+import '../memory_compiler.dart';
+import 'helper.dart';
+import 'test_data.dart';
 
 main(List<String> arguments) {
   asyncTest(() async {
     String serializedData = await serializeDartCore();
 
     if (arguments.isNotEmpty) {
       Uri entryPoint = Uri.base.resolve(nativeToUriPath(arguments.last));
       await analyze(serializedData, entryPoint, null);
     } else {
       Uri entryPoint = Uri.parse('memory:main.dart');
@@ skipping 21 matching lines @@
         test.expectedWarningCount,
         diagnosticCollector.warnings.length,
         "Unexpected warning count.");
     Expect.equals(test.expectedHintCount, diagnosticCollector.hints.length,
         "Unexpected hint count.");
     Expect.equals(test.expectedInfoCount, diagnosticCollector.infos.length,
         "Unexpected info count.");
   }
 }